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Causes Of Extruder Screw Elements Wear

This article explores the causes of extruder screw elements wear. Helps you better understand preventive measures to determine wear and tear.

Causes of extruder screw elements wear

Extrusion is a vital process in the manufacturing industry, with the screw and barrel playing a crucial role. However, the wear and tear of extrusion screw elements can be a significant concern, impacting efficiency and longevity. Let’s delve into the key factors that contribute to wear in these essential components.

extruder screw elements

1. Abrasion-extruder screw elements

One of the primary causes of wear in extrusion screw elements is abrasion. The constant friction and pressure within the extruder barrel create an environment where abrasive wear can thrive.

Hard particles like glass fibers, calcium carbonate, and flame retardants present in the polymer can lead to the gradual erosion of the screw and barrel surfaces. This abrasive phenomenon becomes particularly pronounced at high pressures and temperatures.

To combat this, surface hardening techniques such as nitriding and chrome plating can be employed to enhance the durability of the screw elements.

2. Corrosion-extruder screw elements

Corrosive wear is a result of additives and degraded polymer particles chemically attacking extruder components. Contact with corrosive materials or exposure to high temperatures can give rise to corrosion and pitting on extrusion screw elements.

This corrosive wear is most prevalent in the metering zone, where elevated temperatures and extended material residence times amplify the risk of product degradation. Similar to abrasive wear, surface treatments can mitigate the effects of corrosive wear.

3. Overheating-extruder screw elements

Excessive heat generated during the extrusion process can lead to thermal degradation, directly contributing to wear on screw elements. Uneven heating of the cylinder can exacerbate this issue, emphasizing the importance of maintaining consistent temperature profiles. Implementing proper insulation and cooling systems can help regulate temperatures, mitigating the risk of thermal wear and enhancing the overall performance and lifespan of the extrusion system.

4. Fatigue-extruder screw elements

Repeated stress and pressure cycles over time can result in fatigue wear, gradually weakening extrusion screw elements. This cumulative damage can compromise the structural integrity of the screw, leading to eventual failure.

To counteract fatigue wear, ensuring proper alignment of the screw within the cylinder is crucial. Additionally, regular maintenance and inspections can help identify early signs of fatigue, allowing for timely interventions and preventing catastrophic failures.

5. Other Factors-extruder screw elements

Cold Start: The abrupt starting of the extruder can contribute to wear.

Wrong Material Processing: Using corrosive polymers with unsuitable screws can lead to wear.

Uneven Heating: Inconsistent heating of the cylinder can contribute to wear.

Non-Straightness of the Screw: Lack of straightness in the screw can cause wear.

Incorrect Material: Using inappropriate materials for the screw and cylinder can contribute to wear.

How to Identify the Need for Extrusion Screw Replacement

Recognizing the signs of extrusion screw wear is crucial for maintaining optimal performance and preventing irreversible damage to the extruder and the processed polymer. Here are key indicators and judgment methods to determine when a replacement may be needed:

1. Decreased capacity to process material.

Monitor extruder output; if flow rates decline and are consistently below expected levels, it suggests possible wear.

2. Wear on the screw thread, specifically on the thread crest.

If the gap between the screw thread crest and the cylinder surface widens due to wear, consider replacement.

3. Excessive material escaping above the screw thread.

If there is noticeable material leakage, it indicates wear-related gaps. Evaluate the impact on overall extruder output.

4. Elevated polymer temperatures.

Regularly monitor temperature profiles. If there’s a consistent rise, it could signify wear-related degradation. High temperatures may lead to chemical degradation, impacting polymer properties.

5. Visible changes in polymer characteristics.

Observe changes in polymer appearance and properties. If there’s a noticeable decline in quality, it signals potential wear-related degradation.

For example: Yellowing of molten polymer or the presence of carbon residues.
These visual changes are indicative of thermal degradation. If severe, it may necessitate replacement to maintain product quality.

6. Unusual noise or vibration during extrusion.

Increased noise or vibration is a red flag, suggesting potential mechanical issues related to wear. It requires investigation and may prompt consideration for replacement.

7. Notably higher energy consumption by the extruder.

A significant increase in energy usage may be linked to decreased efficiency due to worn screw elements. It signals the need for a closer examination and potential replacement.

About US – Extruder Screw Elements Manufacturer

Nanjing SiKeRun Machinery Co., LTD. stands as a seasoned industry player with a rich history spanning over 20 years. Specializing in the design, production, and after-sales service of twin screw extruders, our core focus revolves around the meticulous research, development, and manufacturing of parallel twin-screw extruders and premium accessories. We are renowned for providing high-wear-resistant and anticorrosive thread components, demonstrating a commitment to delivering top-notch solutions tailored to the individual needs of our clients.

Our diverse product portfolio encompasses a range of cutting-edge offerings, including twin-screw pelletizers, underwater pelletizers, barrels, screw elements, core shafts, and high-speed side feeders, among other essential accessories. Notably, we serve as a key supplier for spare parts to leading domestic machinery manufacturers, ensuring seamless support for their operations. Additionally, our global reach extends to export markets, with our products finding their way to countries such as Germany, Japan, South Korea, India, Brazil, Taiwan, Singapore, and more.

At Nanjing SiKeRun, we take pride in our commitment to technological excellence and our ability to diagnose and address our customers’ technical challenges. Our customer-centric approach enables us to provide unparalleled solutions, fostering lasting partnerships and solidifying our position as a trusted name in the twin-screw extruder industry.

  • Whatsapp: +86 152 5186 1703
  • email: stacy@skrscrew.com
  • Address: Sanlidian 1, Qingshan Community, Chunhua Street, Jiangning district, Nanjing City

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